Prokaryotic cells differ from eukaryotic cells in several ways. Which of the following structures or features are prokaryotic cells completely lacking?

Introduction / Context:
Prokaryotic cells, such as bacteria, are structurally simpler than eukaryotic cells. A key theme in cell biology is understanding which features are present in eukaryotes but absent in prokaryotes. This question asks you to identify which listed structures or features prokaryotic cells lack, compared with eukaryotic cells.

Given Data / Assumptions:

• The focus is on prokaryotic cells like typical bacteria.
• We are comparing their structure to that of eukaryotic cells.
• Options list membrane bound organelles, nucleolus, nuclear membrane, and a combined option all of the above, plus ribosomes.
• We assume standard textbook definitions of prokaryotic versus eukaryotic organisation.

Concept / Approach:
Prokaryotic cells are characterised by the absence of a true membrane bound nucleus and membrane bound organelles. Their DNA is located in a nucleoid region rather than within a nucleus. They do not have organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, or lysosomes. Because there is no true nucleus, they also lack a nuclear membrane and a nucleolus. However, prokaryotes do have ribosomes, although these ribosomes are smaller than those in eukaryotic cells. Therefore, the correct option is that all three listed features membrane bound organelles, nucleolus, and nuclear membrane are absent, making all of the above the best choice.

Step-by-Step Solution:
Step 1: Recall that prokaryotic cells do not have a true nucleus; their DNA lies in a nucleoid region. Step 2: Because there is no nucleus, they do not have a nuclear membrane surrounding the genetic material. Step 3: Also, without a true nucleus, there is no nucleolus inside a nuclear compartment. Step 4: Recognise that prokaryotes lack membrane bound organelles such as mitochondria, chloroplasts, and Golgi bodies. Step 5: Know that prokaryotes do possess ribosomes for protein synthesis, but these ribosomes are not membrane bound organelles. Step 6: Conclude that membrane bound organelles, nucleolus, and nuclear membrane are all absent in prokaryotes, so all of the above is correct.

Verification / Alternative check:
Comparative cell biology tables consistently list absence of a true nucleus and membrane bound organelles as defining traits of prokaryotic cells. Electron micrographs show bacterial cells with ribosomes and DNA but no nuclear envelope or organelles like mitochondria. The nucleolus, which is involved in ribosomal RNA synthesis in eukaryotic nuclei, is also absent. This evidence supports choosing all of the above as the correct option.

Why Other Options Are Wrong:
Membrane bound organelles such as mitochondria: True that these are absent, but this option alone does not capture all missing features. Nucleolus inside a true nucleus: Also absent, but again only part of the full set of absent features. Nuclear membrane surrounding the genetic material: Absent in prokaryotes, but not the only absent feature. Ribosomes for protein synthesis: Incorrect, because prokaryotes do have ribosomes, although they are of the 70S type rather than 80S.

Common Pitfalls:
Students sometimes mistakenly believe that prokaryotes lack all internal structures, including ribosomes. This is not correct. Prokaryotic cells do have ribosomes for protein synthesis but lack membrane bound compartments. The key distinction is presence or absence of membranes around organelles and the nucleus. Remembering that prokaryotes are simpler but still functional cells helps clarify which structures are missing and which are present.

Final Answer:
Prokaryotic cells lack membrane bound organelles, a nucleolus, and a nuclear membrane, so all of the above features are absent.